1. Field of the Invention
This invention relates to a diaphragm driving device for the lens barrel of a camera, and more particularly to a diaphragm driving device suited for driving a diaphragm blade provided in a lens barrel having a relatively great barrel length.
2. Description of the Prior Art
In a lens barrel having an optical system providing a long focal length, the position of an iris diaphragm is generally remote from the imaging plane and thus, a diaphragm driving ring rotatable to provide diametral displacement to a diaphragm blade is disposed at a position remote from the mount portion for a camera.
As an automatic diaphragm mechanism for driving a diaphragm blade in response to the shutter release of a camera, there is one designed such that the movement range of a connecting lever positioned between the diaphragm interlocking device of the camera and diaphragm driving ring is limited by a cam member operatively associated with an aperture value setting operating ring rotatably provided around the outer periphery of a lens barrel, and if the automatic diaphragm mechanism of such construction is applied to a lens barrel having a relatively great barrel length, the member such as the connecting lever will necessarily become long and the construction and arrangement of the device must be improved upon to avoid occurrence of any operational error attributable to the elastic strain or the like of the material and the bulky size of the device.